Quantum memory and information processing method using the same

A quantum memory comprising:

• memory cells each comprising a physical system ensemble, the physical system ensemble comprising physical systems configured to have a total angular momentum of magnetic sublevels, quantum information of the physical system ensemble being expressed by a quantum state of whole amount of the total angular momentum of the physical systems, and the memory cells including two storage memory cells storing the quantum state and a transfer memory cell transferring the quantum state, only two of the memory cells being present on a straight line;
• a magnet configured to apply a magnetic field to the two storage memory cells and the transfer memory cell;
• a first light source configured to irradiate the two storage memory cells and the transfer memory cell with right-handed or left-handed polarized light;
• a second light source configured to simultaneously irradiate one of the two storage memory cells and the transfer memory cell with a laser beam;
• and
• a detector detecting a polarization state of the laser beam.

An information processing method using a quantum memory in which memory cells are provided, each of the memory cells being formed of a physical system ensemble, the physical system ensemble comprising physical systems configured to have a total angular momentum of magnetic sublevels, quantum information of the physical system ensemble being expressed by a quantum state of whole amount of the total angular momentum of the physical systems, at least one of the memory cells being used as a transfer memory cell A transferring the quantum state, memory cells other than the transfer memory cell A being used as storage memory cells storing the quantum state, and in which a set of two arbitrary memory cells V and B is selected from the storage memory cells and the quantum state of the memory cell V is transferred to the memory cell B, the method comprising:

• applying a magnetic field to each memory cell and irradiating each memory cell with right-handed or left-handed polarized light to establish an energy state in which the total angular momentum of the entire physical system ensemble forming each memory cell has a particular value;
• simultaneously irradiating only the two memory cells A and B with one laser beam, detecting a polarization state of the laser beam transmitted through both memory cells, and generating entanglement for the memory cells A and B;
• and
• simultaneously irradiating only the two memory cells A and V with one laser beam, detecting a polarization state of the laser beam transmitted through both memory cells, and teleporting the quantum state of the memory cell V to the memory cell B in which the entanglement with the memory cell A has been generated.